A series of explosions set off by a team of scientists is expected to rattle the Mount St. Helens in Washington State on Wednesday as researchers map the volcano's interior, whose 1980 eruption was the worst in American history.
Mount St. Helens, approximately 150 km (95 miles) south of Seattle and 50 miles (80 km) north of Portland, exploded in a hot ash eruption in May 1980, scattering debris over a large area, killing 57 people and causing more than $1 billion in damage.
Scientists throughout the United States are seeking to get a better handle on the 8,300-foot (2,530-meter) volcano's magma stores and internal workings to strengthen alert systems before eruption.
"Mount St. Helens and other Cascade Range volcanoes challenge metropolitan centers from Vancouver to Portland," said lead scientist Alan Levander of the University of Rice in Houston in a statement.
"We would like to understand better their inner workings to help predict when they could erupt and how serious those eruptions are likely to be," he said.
Geophysicists from around the US were to begin running seismic waves across the interior of the volcano on Wednesday by firing "shots" at the mountain to install deep underground mapping instruments.
The instruments will help create a kind of CAT scan on the inside and will "illuminate the architecture of the greater Mount St. Helens magmatic system from slab to floor," according to project researchers called Imaging Magma Under St. Helens, or iMUSH (imush.org/)
By July 31, a total of 23 boreholes 80 feet (24 meters) deep would have been built, said researcher Steve Malone.
"These shots are taken at night to provide the best chance to capture good signals without other noises like wind or vehicle traffic being present," Malone said.
People living around Mount St. Helens were unlikely to feel the shots because of their depth however, scientists said, their inclusion approximates an earthquake of magnitude two.
The U.S. In May Geological survey said that inside Mount St. Helens, magma levels were gradually rising, but there was no indication of an imminent eruption.
(Reporting by Victoria Cavaliere; Editing by Cynthia Johnston and Sandra Maler)